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Process Capabilities

Introduction

SAES Memry is proud to offer a diverse portfolio of capabilities and services dedicated to meeting the complex geometric and critical tolerance requirements of next generation medical device designs. Our commitment to continuous improvement and a dedicated focus on proactively anticipating the design and production challenges facing our customers, mandates that SAES Memry invest in world class processing capabilities that are supported by recognized thought leaders in the field of shape memory alloy solutions for the medical device market.

Clean Rooms


SAES Memry has recently expanded our cleanroom facilities to accommodate the growing need to have products manufactured/assembled in a clean environment. Our extensive ISO Class 7 Cleanrooms are utilized for production and assembly of devices or components requiring low bio-burden/pyrogen content. Products can be double bagged or sealed in peel pouches for shipment.

Coatings and Platings

SAES Memry offers coatings for lubricity and platings for radiopacity. These may be applied to Nitinol in most any form.

  • Coatings:
    • Hydrophilic Coating can be applied to guidewires and other devices to promote lubricity. SAES Memry has both R&D and high volume coating equipment dedicated for this purpose. This coating is typically applied to a polymeric coated substrate (eg. Jacketed guidewire), however it may also be applied to bare Nitinol.
    • PTFE and FEP are Hydrophobic coating options for lubricity promotion. Unfortunately both cure at temperatures/times that risk altering the thermo-mechanical properties of Nitinol substrates. SAES Memry now offers a low cure temperature PTFE option that significantly reduces this problem while maintaining a high level of lubricity.
    • Parylene is a good option for dielectric strength enhancement or for mild lubricity. The main advantages of this coating are its room temperature and vacuum deposition application. This prevents any temperature induced thermo-mechanical changes. The vacuum deposition process allows for coating in the tightest of spaces.
  • Platings:
    • Gold, Platinum and Tantalum can be plated over Nitinol substrates. These platings are typically used for radiopacity or to improve solder wetting.

Coiling

SAES Memry manufactures coils from Nitinol and traditional materials (eg. Stainless steel). We specialize in fabrication of microcoils for various medical applications. Our coils are sold directly as raw materials or used to produce higher level assemblies here at SAES Memry (eg. Guidewires).

  • Materials: Nitinol, Stainless steel, Platinum, Tungsten, Gold, MP35N
  • OD Range: From 0.004"
  • Wire Diameter Range: From 0.001"
  • Tight wound, open or variable pitch
Custom Grinding

SAES Memry is capable of grinding Nitinol to virtually any form using both conventional and state of the art grinding equipment. We can produce everything from simple guidewire style geometries to sophisticated grinds for more custom applications such as locking features. SAES Memry also produces a full range of needle tip and trocar geometries.

  • Typical applications:
    • Guidewires
    • Needle tips
    • Overmold retention features
    • Locking features

Joining and Welding

SAES Memry has many options for joining Nitinol to itself or other materials.

  • Welding:
    • Laser, Plasma, TIG and Resistance welding is extensively performed by SAES Memry to join Nitinol to itself, to seal Nitinol tubes, or to produce atraumatic balls on wires for specialized applications.
  • Mechanical:
    • Crimping is one of the best methods to join Nitinol to itself or dissimilar materials. Crimps are typically made from either Nitinol or stainless steel tubing. SAES Memry is particularly adept at crimping wireformed stents, in both lap and butt joint configurations. Pins or other mechanical locking features are also effective means for joining Nitinol to dissimilar materials
  • Soldering:
    • SAES Memry can solder Nitinol to itself or to dissimilar metals. Although this technique is robust, applications are somewhat limited to geometries that allow thorough cleaning of flux residue. SAES Memry typically uses Silver-Tin solders.
  • Adhesives
    • Adhesives can be an attractive option for joining Nitinol to dissimilar materials. SAES Memry uses many different adhesive types (UV cure, heat cure, room temperature cure) depending on the application or customer requirements.

Laser Cutting

Recent infrastructure investments in our laser cutting work center, including upgrades in laser micro-machining capabilities and production capacity, ensure that SAES Memry is well positioned to service the complex geometries and demanding tolerances of next generation laser cut stent designs. SAES Memry is not limited to stents as we regularly cut sophisticated geometries from tube, wire, sheet and strip for various applications.

  • Materials:
    • Nitinol
    • Other materials for medical applications (Stainless, Cobalt-Chromium Alloys, Elgiloy, etc.)

Melting


Please refer to the SSM Smart Materials Website for information on our Nitinol Mill Products.

Shape Setting and Heat Treatment

Our extensive Nitinol processing experience allows us to develop cost effective processes for fabrication of formed components from Nitinol wire, tubing, sheet, strip and other laser cut components. Proper tooling design, tooling material selection, heat treatment method and process parameters are all vital to success when forming Nitinol.
Chosen specifically for each application, SAES Memry utilizes the following heat treatment methods for shape setting of Nitinol components:

  • Molten Salt Bath
  • Fluidized Bed
  • Air Furnace (box or tube)
  • Heated Die
  • RF Induction
  • Resistance
  • Forced Heated Air

Surface Treatment

SAES Memry offers many surface treatment options for raw materials and finished components/assemblies. Following are descriptions of the various options:

  • Hard Black Oxide - A thick Nitinol oxide layer created by annealing the material in an oxidizing environment (rather than an inert environment) during processing. The surface is not cleanable and must be removed for medical applications. This treatment is preferred for select downstream processes and is only offered on Nitinol wire.
  • Black (or Dark) Oxide - A relatively thick Nitinol oxide layer created by annealing the material in an oxidizing environment (rather than an inert environment) during processing. This finish is typically shiny and dark in color.
  • Drawn Bright - A thinner Nitinol oxide layer typically created by annealing the material in an inert environment. Many Nitinol products come standard with this finish (sometimes referred to as Light Oxide), which is typically shiny and can vary in color.
  • Chemical Etch (or Pickle) - A chemical means to remove oxide from Nitinol. The process is not selective, therefore the initial and final texture are similar. Chemical Etching can be useful for removing the recast layer formed by laser cutting or wire EDM.
  • Electro-polish (EP) - An electro-chemical process for polishing materials, resulting in a smoother finish than the part had originally. Electropolishing improves the corrosion resistance of Nitinol by improving the surface finish. SAES Memry passivates all electro-polished parts as standard practice.
  • Mechanical-polish - A mechanical means to remove oxide or recast. Mechanical polishing can be adjusted for minimal surface modification up to a full, shiny polish.
  • Passivation - A chemical treatment that creates a Titanium-rich oxide layer that improves the corrosion resistance of the original surface.
  • Acid Clean - A chemical treatment typically performed on small diameter Nitinol tubes to remove visible oxide on both the ID and OD. This process yields exceptionally clean tubes inside and out. The resulting satin finish is useful for downstream bonding or soldering.
  • Centerless Grinding - An abrasive machining technique used to reduce the outside diameter of wire or tube. This process results in a shiny, bare metal surface with extremely fine circumferential grinding marks.
  • Microblasting - Scaled down version of sandblasting using very fine abrasive media, resulting in a matte, finely textured bare metal surface. This process is useful for removing the recast layer after laser cutting or Wire EDM. This process can be used selectively for adhesion promotion when using epoxies or solder.
Testing and Analysis

SAES Memry provides a full range of capabilities for in process, final quality, and contract testing and analysis requirements. The analytical services provided are as follows. Other services may be provided upon request.

  • Mechanical Properties
    • Tensile Testing
    • Radial Force Testing
    • Fatigue Testing
      • RBT (Rotating Beam Testing)
      • 3-Point Bend Testing
      • 4-Point Bend Testing
  • Physical Properties
    • Chemical Analysis
    • Compositional Analysis
    • Metallographic Analysis
    • Inclusion Analysis
    • XRD (X-Ray Diffraction)
  • Transformation Temperature
    • DSC (Differential Scanning Calorimetry)
    • BRF (Bend and Free Recovery)
    • CLD (Constant Load Dilatometry)
  • Microscopy
    • Optical Microscopy
    • SEM (Scanning Electron Microscopy)
    • EDS (Energy Dispersive X-Ray Spectroscopy)
    • Automated Precision Measurement
  • Other
    • Corrosion Evaluation
    • Biocompatibility
    • Surface Analysis
    • Mechanical and Functional Testing
    • FEA (Finite Element Analysis)
    • Failure Analysis
Wire EDM

SAES Memry has Wire EDM capabilities for specialized machining of Nitinol components. Many sophisticated geometries (eg. Needle tips) may be produced by Wire EDM, specifically those which require burr free finishes and precise tolerances.

  • Advantages:
    • Burr Free Finish
    • Minimal Heat Affected Zone
    • Zero Force on Workpiece
    • Can Machine Thick Workpieces